An axial flux electrical machine comprises a first flux generating assembly, a second flux generating assembly, a shaft and a speed controller. The shaft has an axis of rotation. Each of the first flux generating assembly and the second flux generating assembly is rotationally located on the shaft in axial juxtaposition to one another, with the first flux generating assembly being axially separated from the second flux generating assembly by a separation distance. The speed controller is configured to modify a magnetic field generated by either of the first flux generating assembly and the second flux generating assembly so as to control a rotational speed of the electrical machine.

Fluid systems are described herein. An example embodiment of a fluid system has a first body portion, a second body portion, a plurality of supports, a plurality of fluid pressurizers, and a plurality of ducts. The first body portion and the second body portion cooperatively define an injection opening, a suction opening, and a channel that extends from the injection opening to the suction opening. The fluid pressurizer is disposed within the channel cooperatively defined by the first body portion and the second body portion. Each duct of the plurality of ducts is disposed within the channel cooperatively defined by the first body portion and the second body portion.

Fluid systems are described herein. An example embodiment of a fluid system has a first body portion, a second body portion, a plurality of supports, a plurality of fluid pressurizers, and a plurality of ducts. The first body portion and the second body portion cooperatively define an injection opening, a suction opening, and a channel that extends from the injection opening to the suction opening. The fluid pressurizer is disposed within the channel cooperatively defined by the first body portion and the second body portion. Each duct of the plurality of ducts is disposed within the channel cooperatively defined by the first body portion and the second body portion.

A device including a resonant array of a plurality of synthetic jet generators where neighboring jet generators are coupled, resulting in the potential for constructive and destructive interference between jets of the plurality of synthetic jet generators depending on the relative phase of a corresponding plurality of drive signals to plurality of synthetic jet generators. The device also includes a controller configured to control the relative phase of the corresponding plurality of drive signals to effect a change in a first jet emitted by a first synthetic jet generator of the plurality of synthetic jets by changing a given phase of a second jet emitted by a second synthetic jet generator of the plurality of synthetic jet generators.

A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle (501) defining a duct, and a fan located therewithin. The fan comprises a hub arranged to rotate around a rotational axis (A-A) and a plurality of blades attached thereto. Each blade has a span (r) from a root at the hub defining a 0 percent span position (r=0) to a tip defining a 100 percent span position (r=1) and a plurality of span positions therebetween (r [0, 1]), and leading and trailing edges defining, for each span position, a chord therebetween to having a chord length (c). For each of said plurality of blades, the ratio of chord length at the 0 percent span position (c.sub.hub) to chord length at the 100 percent span position (c.sub.tip) is 1 or greater.

A boundary layer ingestion fan system for location aft of the fuselage of an aircraft includes a nacelle (501) defining a duct (502), and a fan (503) located therewithin. The fan comprises a hub which rotates around a rotational axis (A-A) and a plurality of blades attached thereto. Each blade has a span (r) from a root at the hub defining a 0 percent span position (r=0) to a tip defining a 100 percent span position (r=1) and a plurality of span positions therebetween (r [0, 1]), a leading edge and a trailing edge defining, for each span position, a chord therebetween having a chord length (c), and a blade thickness (t) defined for each span position thereof. For each blade, a ratio of thickness at the 0 percent span position (t.sub.hub) to chord length is 0.1 or greater.

A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle defining a duct, and a fan located within the duct. The fan comprises a hub arranged to rotate around a rotational axis (A-A) and a plurality of blades attached to the hub.

A blade blockage, which is the ratio of the blade thickness to the product of the circumferential pitch and the cosine of a blade inlet angle (t/s.Math.cos.sub.1), is 0.25 or greater at the 0 percent span position.

A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle defining a duct, and a fan located within the duct. The fan comprises a hub arranged to rotate around a rotational axis (A-A) and a plurality of blades attached to the hub, each of which has a span from a root at the hub defining a 0 percent span position (r.sub.hub) to a tip defining a 100 percent span position (r.sub.tip) and a plurality of span positions therebetween (r[r.sub.hub, r.sub.tip]). A hub-tip ratio of the fan, defined as the ratio of the diameter of the hub to the diameter of the fan measured at the leading edge of the blades, is from 0.45 to 0.55.

A cross flow fan to be incorporated into an aircraft comprises a cross flow fan rotor to be positioned in an aircraft, a drive arrangement for the cross flow fan rotor, and a plurality of vanes positioned downstream of the cross flow fan rotor. An aircraft is also disclosed.

A leading edge structure (11) for a flow control system of an aircraft (1) including a leading edge panel (13) surrounding a plenum (17) that extends in a span direction (19). The leading edge panel (13) has a first side portion (21) extending from a leading edge point (23) to a first attachment end (25) and a second side portion (27) opposite the first side portion (21), extending from the leading edge point (23) to a second attachment end (29), wherein the leading edge panel (13) comprises an inner surface (33) facing the plenum (17) and an outer surface (37) in contact with an ambient flow (39), and wherein the leading edge panel (13) comprises a plurality of micro pores (45) forming a fluid connection between the plenum (17) and the ambient flow (39).